The Alternate Reality Game genre inspires a mode of play in which the participants choose to act as if the game world was real. Jane McGonigal has argued that one of the most attractive features of an ARG is the ‘Pinnochio’ effect: at the same time that the players deeply long to believe in them, it is in reality impossible to believe in them for real. In this article, we study “Sanningen om Marika”, a game production where fact and fiction was blurred in a way that made some participants believe that the production was reality rather than fiction, whereas other participants found the production deeply engaging. We discuss the different participant interpretations of the production and how it affected the players´ mode of engagement. We also outline some of the design choices that caused the effect.